Ore-roasting furnace.



N0. 798,844. PATENTED SEPT. 5, 1905. F. H. TREGO.

ORB ROASTING FURNACE. urmonxon FILED JAN. 26, 1904.

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PATENTED SEPT. 5,.1905.

F. H. TREGO.

ORE ROASTING FURNACE.

APPLIOATION FILED JAN. 25, 1904.

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No. 798,844. PATENTED SEPT. 5, 1905. F. H. TRBGO. ORB ROASTING FURNACE.

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PATENT OFFICE.

FRANK H. TREGO, OF POTOSI, \VISCONSIN.

ORE-ROASTING FURNACE.

Specification of Letters Patent.

'IPatented Sept. 5, 1905.

Application filed January 25, 1904. Serial ITO-190,577.

To all 11:71pm. it many concern.

Be it known that I, FRANK H. Tnnoo, a citizen of the United States, residing at lotosi, in the county of Grant and State of \Visconsin, have invented certain new and useful Improvements in Ore-Roasting Furnaces, of which the following is a specification.

My invention relates to ore-roasting furnaces such as are designed to effect the oxidizing of zinc and other ores through the agency of heat and oxygen, having reference. more particularly to that type of furnace employing a circular rotary hearth having an ore-receiving surface, with a lire-box or combustion-chamber and an outlet-flue or chi-mney located at diametrically opposite points adjacent thereto and a radial series of stationary plows adapted to distribute the ore received centrally of the hearth over the latter in gradually-widening circles, finally discharging it when roasted from the periphery of the hearth.

My invention has for its leading object to increase the simplicity and durability of furnaces of this character, which being subjected to a high degree of heat frequently become weakened or ineffective at vulnerable points.

Other more specific objects of the invention are to effect a freer admission of oxygen to the hearth and a more uniform distribution of the heat throughout the latter, to increase the longevity and efficiency of the stationary plows, to provide simple and expeditious means for supplying the ore to the furnace in uniform quantities as required and for conveying away the roasted ore, and to dispense with the use of central spindles or bearings for the hearth, which on account of the severe effects of the heat are objectionable.

To these ends my invention resides in an ore-roasting furnace of the character indicated possessing the novel improved features of construction and operation, substantially as hereinafter described, and more particularly pointed out in the claims appended to this specification.

In order that my invention may be completel y understood, 1 have illustrated the same in an approved form in the accompanying drawings, wherein Figure 1 is a side elevational view of the furnace complete. Fig. 2 is a top plan view thereof with certain parts in horizontal section to more clearly disclose the interior construction. Fig. 3 is a vertical central sectional view through the fire-box and rotary hearth. Fig. & is a top plan view, partly in horizontal section, of the series of hollow plows and their hollow connecting member. Fig. 5 is a side elevational view, partly in vertical section, of the parts shown in Fig. 4; and Fig. 6 is an enlarged detail View, in Vertical section, on the line 6 6 of Fig. Hooking in the direction indicated by the arrows.

Referring to the drawings, 10 designates the annular furnace-wall, and 11 a domed top or cover, which latter is supported atits apex on the annularly-shouldered upper end of a stationary central pillar 12 of considerable diameter.

13 designates the circular hearth, having a central opening 1%, loosely litting an annular groove 15 in the pillar 12 and provided on its under surface with a circular depending rail or flange 16, which rests on a series of annularly-grooved rollers 17, rotatably mounted on stationary supporting-blocks 18, disposed at intervals around the central pillar 12, whereby the hearth is supported with capacity for rotation. The means herein shown for effecting the rotation of the hearth comprises a large annular bevel-gear 19, suitably secured to the under side of the hearth and surrounding and concentric with the pillar 12, a bevel-pinion 20, mounted on a horizontal shaft 21, engaging the gear 19, the shaft being driven through power applied thereto by any suitable or convenient means. (Not shown.) 7

As a means for supplying the ore to the hearth I provide a screw conveyor 22, suitably mounted to bring its discharging end directlyover a hopper 23, which latter is mounted on the upper end of the pillar 12 and has an inclined discharge-chute 2st lying within the pillar and terminating at one side of the latter directly above the inner portion of the hearth, while for the purpose of carrying off the oxidized ore I provide a similar conveyer 25, mounted in a trough 26, disposed tangentially of and beneath the outer periphery of the hearth directly below the outermost of a series of stationary inclined plows 27, arranged radially of and directly above the upper surface of the hearth.

28 designates the usual lire-box or combustion-chamber, and 29 the chimney containing the outlet-flue 30, the lire-box and chimney being located at diametrically opposite points adjacent to the periphery of the hearth.

The series of plows 27 are made of hollow metal connected to and depending from a hol- IIO low bar 31, which latter is secured at one end in the pillar 12 and at the other end in theinner wall of the chimney 29, the inlet from the roasting-chamber to the chimney being divided by the partition 32, supporting said bar, making a pair of companion smoke and flame passages 33, lying, respectively, on either side thereof. The hollow bar 31 is tapped at its outer end by a water-inlet pipe 34 and at its inner end within the pillar 12 by a water-discharge pipe 35. The interior of the hollow bar 31 is in free communication with the interiors of the several plows 27, as more particularly illustrated in Figs. 5 and 6, and the inlet-pipe 34 is connected to asuitabl'epump,

head, or other source of cold-water supply,-

whereby a steady flow of cold water is maintained through the bar 31 and the plows 27, serving to keep the temperature of the latter down to such a point as will not injure the plows or render them inefficient for their intended purpose under the great heat of the furnace.

It will be observed that the diameter ofthe hearth 13 is considerably less than the internal diameter of the'annular furnace-wall 10, within the lower portion of which said hearth is disposed. This provides for an annular air-inlet passage around the'outer margin of the hearth, affording opportunity for thefree and uniform ingress of air all around the hearth to supply oxygen to support combustion and effect the oxidizing of the ore.

In the operation of the furnace the 'ore is continuously fed to the hearth'by the conveyer 22 in quantities determined by the .speed of the conveyer relatively to the speed of rotation of the hearth. The ore is distributed upon the hearth during the roasting'operation by the plows 27, which serve to gradually move itin a continuous spiral from the point of admission near the center of the hearthto the point of discharge at the outer periphery thereof above the conveyer 25. Thefreeadmanner,

to divide the flames effectively and make them cover the entire hearth at once at the same time that it obviates the necessity of central spindles-or bearings which are liable to become ineffective through the high temperature employed. The circulation of cold water through the plows keeps the latter relatively cool, preventing deformation thereof through the joint action of the heat and pressure of the ore and insuring their highest efiiciency at all times.

Minor variations and detail changes of structure may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim 1. In-an ore-roasting furnace, the combination with an annular furnace-wall and astationary pillar concentric therewith and extending to-the foundation of the furnace, of a circular hearth within said wall mounted to rotate around said pillar,a domed top'or cover mounted on the upper end of said pillar,-a radiallydisposed hollow bar secured at its inner end in said pillar, a water-discharge pipe mounted in said pillar and communicating with the inner end of said hollow bar, a water-inlet pipe communicating with the outer end of saidhollow bar,a series of hollow plows connected to and depending'frorn said hollow bar, and means for imparting rotation to said hearth, substantially as described.

2. In an 'ore-roastingfurnace, the combination with an 'annularfurnace-wall and a stationary pillar concentric therewith annularly shouldered at the top and annularly grooved W. T. BROWN, E. B. SMITH. 

